Tube for a bicycle

Abstract

A tube for a bicycle has a body, an indented portion, and a machined hole. The indented portion is radially recessed in the body and has an outer bottom surface, an outer annular surface, and a first round corner being a curved surface smoothly connecting an outer tube surface of the body and the outer annular surface. The machined hole is formed through the outer bottom surface of the indented portion and has an area being less than an area of the outer bottom surface. The indented portion formed around the machined hole distributes stress to prevent cracking occurring from an edge of the machined hole. The structural strength of the tube is increased under a same total weight.

What is claimed is: 
     
       1. A tube for a bicycle, the tube comprising:
 a body made of a material selected from one of a metallic material and a composition material and having
 an outer tube surface; 
 an inner tube surface; 
 an inner hole longitudinally formed through the body; and 
 a tube thickness defined between the outer tube surface and the inner tube surface; 
 
 an indented portion radially recessed in the body from the outer tube surface toward the inner tube surface of the body and having
 a thickness being equal to the tube thickness of the body; 
 an outer bottom surface; 
 an outer annular surface formed around the outer bottom surface to form an opening gradually larger outward from the outer bottom surface of the indented portion; 
 a first round corner being a curved surface smoothly connecting the outer tube surface of the body and the outer annular surface of the indented portion; and 
 an angle formed between a tangent line, which is tangent to the outer annular surface, and a tangent plane, which is tangent to the outer tube surface of the body, being less than 90 degrees and greater than or equal to 15 degrees; and 
 
 a machined hole formed through the outer bottom surface of the indented portion and communicating with the inner hole of the body and having an area being smaller than an area of the outer bottom surface of the indented portion, 
 wherein the indented portion has a recessed depth in the body, the recessed depth ranging from 1 time to 3 times of the tube thickness, and 
 a distance between two radially opposite theoretical intersections of outer edges of the outer annular surface and the outer tube surface is 1.3 times to 3 times of a distance between two radially opposite edges of the machined hole. 
 
     
     
       2. The tube for a bicycle as claimed in  claim 1 , wherein the first round corner is rounded with a radius of a maximum of 5 times of the tube thickness and a minimum of 1 time of the tube thickness. 
     
     
       3. The tube for a bicycle as claimed in  claim 1 , wherein the first round corner has a continuous curvature having a dimension equivalent to a radius of a maximum of 5 times of the tube thickness and a minimum of 1 time of the tube thickness. 
     
     
       4. The tube for a bicycle as claimed in  claim 1 , wherein the angle of the indented portion is less than or equal to 75 degrees and greater than or equal to 30 degrees. 
     
     
       5. The tube for a bicycle as claimed in  claim 2 , wherein the angle of the indented portion is less than or equal to 75 degrees and greater than or equal to 30 degrees. 
     
     
       6. The tube for a bicycle as claimed in  claim 3 , wherein the angle of the indented portion is less than or equal to 75 degrees and greater than or equal to 30 degrees. 
     
     
       7. The tube for a bicycle as claimed in  claim 4 , wherein an angle is formed between the outer bottom surface of the indented portion and the outer annular surface. 
     
     
       8. The tube for a bicycle as claimed in  claim 5 , wherein an angle is formed between the outer bottom surface of the indented portion and the outer annular surface. 
     
     
       9. The tube for a bicycle as claimed in  claim 6 , wherein an angle is formed between the outer bottom surface of the indented portion and the outer annular surface. 
     
     
       10. The tube for a bicycle as claimed in  claim 4 , wherein a second round corner is formed between the outer bottom surface of the indented portion and the outer annular surface, is a curved surface smoothly connecting the outer annular surface and the outer bottom surface, and is rounded with a radius of a maximum of 5 times of the tube thickness. 
     
     
       11. The tube for a bicycle as claimed in  claim 5 , wherein a second round corner is formed between the outer bottom surface of the indented portion and the outer annular surface, is a curved surface smoothly connecting the outer annular surface and the outer bottom surface, and is rounded with a radius of a maximum of 5 times of the tube thickness. 
     
     
       12. The tube for a bicycle as claimed in  claim 6 , wherein a second round corner is formed between the outer bottom surface of the indented portion and the outer annular surface, is a curved surface smoothly connecting the outer annular surface and the outer bottom surface, and is rounded with a radius of a maximum of 5 times of the tube thickness. 
     
     
       13. The tube for a bicycle as claimed in  claim 4 , wherein a second round corner is formed between the outer bottom surface of the indented portion and the outer annular surface, is a curved surface smoothly connecting the outer annular surface and the outer bottom surface, and has a continuous curvature having a dimension equivalent to a radius of a maximum of 5 times of the tube thickness. 
     
     
       14. The tube for a bicycle as claimed in  claim 5 , wherein a second round corner is formed between the outer bottom surface of the indented portion and the outer annular surface, is a curved surface smoothly connecting the outer annular surface and the outer bottom surface, and has a continuous curvature having a dimension equivalent to a radius of a maximum of 5 times of the tube thickness. 
     
     
       15. The tube for a bicycle as claimed in  claim 6 , wherein a second round corner is formed between the outer bottom surface of the indented portion and the outer annular surface, is a curved surface smoothly connecting the outer annular surface and the outer bottom surface, and has a continuous curvature having a dimension equivalent to a radius of a maximum of 5 times of the tube thickness. 
     
     
       16. The tube for a bicycle as claimed in  claim 4 , wherein the material of the body is selected from one of an aluminum alloy and a carbon fiber. 
     
     
       17. The tube for a bicycle as claimed in  claim 5 , wherein the material of the body is selected from one of an aluminum alloy and a carbon fiber. 
     
     
       18. The tube for a bicycle as claimed in  claim 6 , wherein the material of the body is selected from one of an aluminum alloy and a carbon fiber. 
     
     
       19. The tube for a bicycle as claimed in  claim 14 , wherein the material of the body is selected from one of an aluminum alloy and a carbon fiber.